Communications System and Method for Determining an Exclusion Zone in Proximity to a Wireless Communications System

1. A wireless communications method comprising: defining an exclusion zone in proximity to a first wireless communications system, by transmission of a system beacon signal from a gateway of the first wireless communications system, the first wireless communications system using a different radio access network from that of a second wireless communications system, the exclusion zone indicating that any user equipment within the exclusion zone is not permitted to communicate with the second wireless communications system using a portion of spectrum which has been pre-assigned to the first wireless communications system and which is currently re-assigned to the second wireless communications system by a spectrum assignment process; calculating a difference between a measured level of interference and a maximum acceptable level of interference inflicted on the first wireless communications system, controlling a local size of a part of the exclusion zone in dependence on the difference; transmitting from a base station of the first wireless communications system a local beacon signal, the strength of which indicates only the size of a local part of the exclusion zone, and adjusting the strength of the local beacon signal in order to control the local size of the part of the exclusion zone.

2. The method of claim 1 further comprising: storing a mapping table of the level of interference against the local size of the part of the exclusion zone, and using the mapping table to control the local size of the part of the exclusion zone in dependence on the difference.

3. The method of claim 1 wherein controlling the local size of the part of the exclusion zone comprises varying the size of the exclusion zone non-uniformly around the perimeter of the exclusion zone.

4. The method of claim 1 wherein controlling the local size of the part of the exclusion zone comprises moving one or more portions of the perimeter of the exclusion zone towards or away from a central region of the exclusion zone.

5. The method of claim 4 further comprising: moving the one or more portions independently of other portions of the perimeter.

6. The method of claim 1 wherein controlling the local size of the part of the exclusion zone comprises dynamically varying the local size.

7. A method of operating a controller for use with a wireless communications system comprising: receiving a signal which is indicative of a level of interference inflicted on a first wireless communications system, the first wireless communications system having first wireless communications system base stations serving user equipments and a gateway; calculating a difference between the level of interference inflicted on the first wireless communications system and a maximum acceptable level of interference; controlling a size of a part only of an exclusion zone in dependence on the difference, the exclusion zone indicating that any user equipment within the exclusion zone is not permitted to communicate with a second wireless communications system using a portion of spectrum which was pre-assigned to the first wireless communications system and which is currently re-assigned to the second wireless communications system by a spectrum assignment process; and transmitting to the first wireless communication system a control signal which is indicative of the size of the exclusion zone, wherein the control signal is indicative of a system beacon signal transmitted from the gateway of the first wireless communication system to establish the exclusion zone in proximity to the first wireless communication system, and wherein the control signal further indicates the power of a local beacon signal transmitted from a base station of the first wireless communication system and the strength of the local beacon signal is adjusted in order to control only the local size of the part of the exclusion zone.

8. The method of claim 7 further comprising: storing a mapping table of the level of interference against the local size of the part of the exclusion zone, and using the mapping table to control the local size of the part of the exclusion zone.

9. The method of claim 7 wherein the controlling a local size of the part of the exclusion zone comprises determining a variation in the size of the exclusion zone which is non-uniform around the perimeter of the exclusion zone.

10. The method of claim 7 wherein the controlling a local size of the part of the exclusion zone comprises determining a movement of one or more portions of the perimeter of the exclusion zone towards or away from a central region of the exclusion zone.

11. The method of claim 10 further comprising: determining the movement of the said one or more portions independently of other portions of the perimeter.

12. A first wireless communication system comprising: a gateway and a plurality of base stations configured to serve a plurality of user equipment, wherein the gateway comprises: exclusion zone circuitry configured to define an exclusion zone in proximity to the first wireless communications system by transmission of a system beacon signal, the first wireless communication system using a different radio access network from that of a second wireless communications system, the exclusion zone indicating that any user equipment within the exclusion zone is not permitted to communicate with the second wireless communications system using a portion of spectrum which has been pre-assigned to the first wireless communications system and which is currently re-assigned to the second wireless communications system by a spectrum assignment process; and wherein one or more of the plurality of base stations comprises: beacon circuitry configured to transmit a local beacon signal, the strength of which indicates only the size of a local part of the exclusion zone; wherein the first wireless communications system is further configured to calculate a difference between a measured level of interference inflicted on the first wireless communications system and a maximum acceptable level of interference; control a local size of a part of the exclusion zone in dependence on the difference; and wherein the one or more base stations are configured to adjust the strength of the local beacon signal in order to control the local size of the part of the exclusion zone.

13. The apparatus of claim 12 further comprising: memory circuitry configured to store a mapping table of the level of interference against the local size of the part of the exclusion zone, wherein the exclusion zone circuitry is configured to use the mapping table to control the local size of the part of the exclusion zone in dependence on the level of interference.

14. The apparatus of claim 12 wherein the exclusion zone circuitry is configured to control the size of the exclusion zone non-uniformly around the perimeter of the exclusion zone.

15. The apparatus of claim 12 wherein the exclusion zone circuitry is configured to move one or more portions of the perimeter of the exclusion zone towards or away from a central region of the exclusion zone.

16. The apparatus of claim 15 wherein the exclusion zone circuitry is configured to move the one or more portions independently of other portions of the perimeter.

17. The apparatus of claim 12 wherein the exclusion zone circuitry is configured to control the local size dynamically.

18. A controller for use with a first wireless communications system, the first wireless communications system having first wireless communications system base stations serving user equipments and a gateway, the controller comprising: communications circuitry configured to determine the desired size of an exclusion zone and to transmit to the first wireless communications system a desired power of a system beacon signal defining the exclusion zone, wherein the system beacon signal is transmitted from the gateway; communications circuitry configured to receive a signal which is indicative of a level of interference inflicted on a first wireless communications system; control circuitry configured to determine a difference between the level of interference inflicted on the first wireless communications system and a maximum acceptable level of interference, and configured to control a local size of a part of an exclusion zone based on the difference; wherein the communications circuitry is configured to transmit to the first wireless communications system a signal which is indicative of the size of part of the exclusion zone wherein the signal indicates the power of a local beacon signal transmitted from the base station of the first wireless communication system and the strength of the local beacon signal is adjusted in order to control only the local size of the part of the exclusion zone, wherein the exclusion zone indicating that any user equipment located within the exclusion zone is not permitted to communicate with a second wireless communications system using a portion of spectrum which has been pre-assigned to the first wireless communications system and which is currently re-assigned to the second wireless communications system by a spectrum assignment process.

19. The controller of claim 18 further comprising: memory circuitry configured to store a mapping table of the level of interference against the local size of the part of the exclusion zone, wherein the control circuitry is configured to use the mapping table to determine the local size of the part of the exclusion zone.

20. The controller of claim 18 wherein the control circuitry is configured to determine a variation in the size of the exclusion zone which is non-uniform around the perimeter of the exclusion zone.

21. The apparatus of claim 18 wherein the control circuitry is configured to determine a movement of one or more portions of the perimeter of the exclusion zone towards or away from a control region of the exclusion zone.

22. The apparatus of claim 21 wherein the control circuitry is configured to determine the movement of the said one or more portions independently of other portions of the perimeter.

23. A non-transitory computer-readable medium storing a computer program which, when run on a computer, causes the computer to perform the method of claim 1 .

24. A non-transitory computer-readable medium storing a computer program which, when run on a computer, causes the computer to perform the method of claim 7 .